Hi All: I have a question about my E30 M3 (1988). My car has developed a noisy diff, and needs either a rebuild or replacement. First question is any recommendations about a quality diff rebuilder? Any members used one previously with good results? Second, the same diff gear set (4.10:1) came in the 1990-1992 E30 318i and iS cars. Would one of these diffs work as a direct replacement for the E30 M3 diff ? Both came as LSD, standard in the M3, and optional in the 318i/iS cars. BMW no longer supports either model with a new unit, and offers no gear sets to rebuild a worn diff. Any comments or suggestions would be appreciated. My car is original with about 122k miles, so originality of a replacement is important to the car's value.